CN112456917A - High-durability concrete and preparation method thereof - Google Patents

Abstract

The application relates to the technical field of concrete, and particularly discloses high-durability concrete and a preparation method thereof. A high-durability concrete comprises water, cement, fly ash, slag powder, an expanding agent, machine-made sand medium sand, machine-made sand fine sand, stones and a composite anti-cracking anti-seepage additive; the composite anti-cracking and anti-seepage additive comprises an anti-cracking and anti-seepage reinforcing agent, hydroxypropyl cellulose, triethyl citrate and polyvinyl butyral; the preparation method comprises the following steps: adding the composite anti-cracking anti-seepage additive into water, and uniformly mixing to obtain an aqueous solution of the additive; mixing various aggregates, and adding 70% of additive aqueous solution for wetting; the other raw materials and the additive water solution with the rest 30 percent of dosage are added to prepare the additive. The high-durability concrete has the advantages that the chloride ion permeability resistance of the concrete is greatly improved, and the durability is obviously improved.

Description

High-durability concrete and preparation method thereof

Technical Field

The application relates to the technical field of concrete, in particular to high-durability concrete resistant to chloride ion permeation and a preparation method thereof.

Background

With the rapid development of economy, the construction industry of China is also rapidly developed, and the use amount of concrete is greatly increased. Corrosion of steel reinforcement is an important factor affecting the durability of concrete structures.

The main reason why the corrosion of steel bars affects the durability and safety of concrete structures is the penetration and diffusion of chloride ions. The addition of the fly ash and the slag powder can improve the chloride ion permeability resistance of concrete, particularly the double addition of the fly ash and the slag powder can obviously improve the chloride ion permeability resistance of the concrete, because the mineral admixture improves the microstructure and the composition of hydration products in the concrete, the blocking capability of the concrete on chloride ion transmission is improved, and the physical and chemical adsorption effect of the mineral admixture ensures that the concrete has stronger curing capability on chloride ions, is beneficial to reducing the transmission speed of the chloride ions in the concrete and improves the chloride ion permeability resistance of the concrete to a certain degree.

With the rapid development of the building industry in China, more and more cross-sea bridges and offshore infrastructures are built, but salt damage in a seawater environment is severe, corrosion of steel bars to a common concrete structure is severe, and the maintenance cost of the concrete building is increased to a great extent.

Disclosure of Invention

In order to improve the chloride ion permeability resistance of concrete, the application provides high-durability concrete and a preparation method thereof.

In a first aspect, the present application provides a high durability concrete, which adopts the following technical scheme:

the high-durability concrete comprises, by weight, 154 parts of water 152-; the composite anti-cracking and anti-seepage additive comprises an anti-cracking and anti-seepage reinforcing agent, hydroxypropyl cellulose, triethyl citrate and polyvinyl butyral, wherein the weight ratio of the anti-cracking and anti-seepage reinforcing agent to the composite anti-cracking and anti-seepage additive is 8 (0.4-0.6) to 0.4-0.6 (0.4-0.6).

By adopting the technical scheme, after the hydroxypropyl cellulose, the triethyl citrate and the polyvinyl butyral are simultaneously doped, the reaction rate of the anti-cracking and anti-seepage reinforcing agent and the calcium hydroxide in the cement paste is greatly enhanced, so that a large amount of ettringite expansion components are generated, the compactness of the concrete is improved, the chloride ion permeability resistance of the concrete is greatly improved, and the durability is obviously improved.

Preferably, the composite anti-cracking and anti-seepage additive also comprises cocoanut diethanolamide and cocamidopropyl dimethylamine ethyl lactone, wherein the weight ratio of the cocoanut diethanolamide to the anti-cracking and anti-seepage enhancer is (0.2-0.4):8, and the weight ratio of the cocamidopropyl dimethylamine ethyl lactone to the anti-cracking and anti-seepage enhancer is (0.2-0.4): 8.

By adopting the technical scheme, the water reducing and dispersing effects of the anti-cracking and anti-seepage reinforcing agent are enhanced, the water-cement ratio and the water consumption of the concrete are reduced, the compactness of the concrete is improved, the chloride ion permeability resistance of the concrete is further optimized, and the durability of the concrete is further improved.

Preferably, the anti-cracking and anti-seepage reinforcing agent is an HZ-2 type anti-cracking and anti-seepage reinforcing agent.

By adopting the technical scheme, the HZ-2 anti-cracking and anti-seepage reinforcing agent integrates the functions of high-efficiency water reduction, cracking resistance, seepage resistance, freezing resistance, slow setting, reinforcement and plasticization, has excellent comprehensive performance and improves the durability of concrete.

Preferably, the swelling agent is a UEA-I type swelling agent.

Preferably, the cement is P042.5 Portland cement.

By adopting the technical scheme, the cement is relatively stable and has low hydration heat.

Preferably, the slag powder is S95 grade slag powder.

By adopting the technical scheme, the mineral admixture improves the microstructure and the hydration product composition inside the concrete, improves the blocking capability of the concrete to chloride ion transmission, has stronger curing capability to chloride ions due to the physical and chemical adsorption effect, is favorable for reducing the transmission speed of the chloride ions inside the concrete, and further improves the chloride ion permeation resistance of the concrete.

Preferably, the stones are 5-25mm continuous graded broken stones.

By adopting the technical scheme, the shrinkage of the concrete is reduced, and the durability of the structure is improved.

Preferably, the fly ash is type II fly ash.

By adopting the technical scheme, the fly ash mineral admixture has a plurality of comprehensive effects such as 'activity effect', 'interface effect', 'micro-filling effect' and 'water reducing effect'.

In a second aspect, the preparation method of the high-durability concrete provided by the application adopts the following technical scheme:

a preparation method of high-durability concrete resisting chloride ion penetration comprises the following steps:

(1) adding the composite anti-cracking anti-seepage additive into water, and uniformly mixing to obtain an aqueous solution of the additive;

(2) mixing the stones, the machine-made sand medium sand and the machine-made sand fine sand, adding the mixture into a stirrer, and stirring for 15-20 seconds to uniformly mix the aggregates;

(3) adding 70% of the water solution of the additive into the stirrer, and stirring for 10-15 seconds to wet the mixed aggregate;

(4) adding cement, slag powder, fly ash and an expanding agent into a stirrer and stirring for 30-40 seconds;

(5) and adding the water solution of the additive with the residual 30 percent of the dosage into a stirrer, and stirring for 1-2 minutes to obtain the high-durability concrete.

By adopting the technical scheme, the composite anti-cracking and anti-seepage reinforcing agent is firstly put into water to prepare the additive aqueous solution, so that the dispersibility of the composite anti-cracking and anti-seepage reinforcing agent in concrete is improved, and the self-action is fully exerted;

mixing the stones, the machine-made sand medium sand and the machine-made sand fine sand, adding 70% of additive aqueous solution, uniformly mixing to fully wet the aggregate, and enabling the aggregate to be easily combined with the gel material;

the cement, the slag powder, the fly ash, the expanding agent and other raw materials are mixed, and then the additive aqueous solution with the residual 30 percent of the dosage is added, so that the cement, the slag powder, the fly ash, the expanding agent and other raw materials are more uniformly fused.

In summary, the present application has the following beneficial effects:

1. meanwhile, after the hydroxypropyl cellulose, the triethyl citrate and the polyvinyl butyral are doped, the reaction rate of the anti-cracking and anti-seepage reinforcing agent and calcium hydroxide in the cement paste is greatly enhanced, so that a large amount of ettringite expansion components are generated, the compactness of the concrete is improved, the chloride ion permeability resistance of the concrete is greatly improved, and the durability is obviously improved;

2. the water reducing and dispersing effects of the anti-cracking and anti-seepage reinforcing agent are enhanced, the water-to-gel ratio and the water consumption of the concrete are reduced, the compactness of the concrete is improved, the chloride ion permeability resistance of the concrete is further optimized, and the durability of the concrete is further improved;

3. the HZ-2 anti-cracking and anti-seepage reinforcing agent integrates the functions of high-efficiency water reduction, cracking resistance, seepage resistance, freezing resistance, retardation, reinforcement and plasticization, has excellent comprehensive performance and improves the durability of concrete.

Detailed Description

The present application will be described in further detail with reference to examples.

TABLE 1 sources of raw materials

Raw materials	Manufacturer of the product
		Cement	Hebei Shenghua environmental protection science and technology Co., Ltd
Fly ash	TIANJIN GUOHUA PANSHAN POWER GENERATION Co.,Ltd.
		Slag powder	TANGSHAN GANGLU IRON & STEEL Co.,Ltd.
Expanding agent	TIANJIN BAOMING Co.,Ltd.
		Machine-made sand medium sand	Xinglong Chengtai building materials Co Ltd
Machine-made fine sand	Xinglong Chengtai building materials Co Ltd
		Stone	Xinglong Chengtai building materials Co Ltd
Anti-cracking seepage-proofing reinforcing agent	HEBEI HEZHONG BUILDING MATERIALS Co.,Ltd.
		Hydroxypropyl cellulose	HEBEI HAOSHUO CHEMICAL Co.,Ltd.
Citric acid triethyl ester	Beijing Han Longda science and technology development Co., Ltd
		Polyvinyl butyral	Tianjin Huachang-derived Industrial and trade Co Ltd
Coconut diethanolamide	Haian national force chemical Co., Ltd
		Cocamidopropyl dimethylamine caprolactone	Shanghai De Ling chemical Co., Ltd

TABLE 2 formulation of a highly durable concrete provided in examples 1-8 (unit: Kg)

TABLE 3 formulation tables (unit: Kg) for a highly durable concrete as provided in comparative examples 1 to 10

The high-durability concrete provided by the above examples and comparative examples is prepared by the following preparation method.

The preparation method of the high-durability concrete comprises the following steps:

(1) adding the composite anti-cracking anti-seepage additive into water, and uniformly mixing to obtain an aqueous solution of the additive;

(2) mixing the stones, the machine-made sand medium sand and the machine-made sand fine sand, adding the mixture into a stirrer, and stirring for 15-20 seconds to uniformly mix the aggregates;

(3) adding 70% of the water solution of the additive into the stirrer, and stirring for 10-15 seconds to wet the mixed aggregate;

(4) adding cement, slag powder, fly ash and an expanding agent into a stirrer and stirring for 30-40 seconds;

(5) and adding the water solution of the additive with the residual 30 percent of the dosage into a stirrer, and stirring for 1-2 minutes to obtain the high-durability concrete.

The above examples and comparative examples were subjected to various property tests, and the test results are shown in tables 4 and 5.

The concrete durability is carried out according to GB/T50082-2009 Standard test method for long-term performance and durability of ordinary concrete and JGJ/T193-2009 evaluation Standard for concrete durability test.

The method for testing the compressive strength of the concrete is carried out by GB/T50081 Standard test method for mechanical properties of common concrete.

TABLE 4 chloride ion Permeability test results (Current Capacity method Q-IV) (Unit C)

	First sample piece	Second sample piece	Third sample piece	Mean value of
					Example 1	623	628	625	625
Example 2	569	572	583	575
					Example 3	621	618	627	622
Example 4	631	615	623	623
					Example 5	628	617	632	626
Example 6	536	522	521	513
					Example 7	486	467	459	471
Example 8	508	517	503	509
					Comparative example 1	678	689	695	687
Comparative example 2	685	693	675	684
					Comparative example 3	672	684	656	671
Comparative example 4	669	687	674	677
					Comparative example 5	656	667	689	671
Comparative example 6	698	676	673	682
					Comparative example 7	677	658	663	666
Comparative example 8	578	587	569	578
					Comparative example 9	568	571	586	575
Comparative example 10	583	574	571	572

As can be seen from Table 4, the high-durability concrete provided by the embodiment of the application has very high chloride ion permeability resistance, and the electric flux passing through the concrete sample piece can reach 650 ℃ or less; and example 7 is the best embodiment, and example 2 is the preferred embodiment.

The difference between the examples 2 and 4 to 5 lies in that the weight ratio of the ingredients used for forming the composite anti-cracking and anti-seepage additive is different, and the detection result shows that: when the weight ratio of the hydroxypropyl cellulose, the triethyl citrate, the polyvinyl butyral to the anti-cracking seepage-proofing reinforcing agent is 0.5:0.5:0.5:8, the high-durability concrete provided by the application has higher chloride ion permeability resistance. The test results of the comparative example 2 and the comparative examples 1 to 7 show that the hydroxypropyl cellulose, the triethyl citrate and the polyvinyl butyral are simultaneously doped to synergistically improve the chloride ion permeability resistance of concrete, and the three are not indispensable. The method is characterized in that hydroxypropyl cellulose, triethyl citrate and polyvinyl butyral are simultaneously doped, so that the reaction rate of the anti-cracking and anti-seepage reinforcing agent and calcium hydroxide in the cement paste can be cooperatively controlled, the speed of generating the ettringite expansion component is better matched with the drying rate of the concrete, and the compactness of the concrete is improved.

It can be seen from comparative examples 2, 6-8 and comparative examples 8-9 that the simultaneous incorporation of cocodiethanolamide and cocamidopropyl dimethylamine glycollide can further improve the chloride ion permeability resistance of concrete, and neither of them is acceptable. The reason is that after the coconut diethanolamide and the cocamidopropyl dimethylamine ethyl lactone are simultaneously added, the water reducing and dispersing effects of the anti-cracking and anti-seepage reinforcing agent are enhanced, the water-gel ratio and the water consumption of the concrete are reduced, and the compaction degree of the concrete is improved.

As can be seen from comparative example 7 and comparative example 10, it was demonstrated that the chloride ion permeability resistance of the concrete into which hydroxypropylcellulose, triethyl citrate, polyvinyl butyral, cocodiethanolamide, cocoamidopropyl dimethylamine glycolide were simultaneously incorporated was higher than that of the concrete into which cocodiethanolamide, cocoamidopropyl dimethylamine glycolide were simultaneously incorporated.

TABLE 5 test results of various properties of the concretes in examples 1 to 6 and comparative examples 1 to 10

Detecting items	Apparent density, kg/m3	28d compressive strength, MPa	Slump, mm
				Example 1	2390	51.2	205
Example 2	2410	52.3	210
				Example 3	2400	51.6	205
Example 4	2390	50.9	205
				Example 5	2400	51.3	205
Example 6	2430	53.2	215
				Example 7	2450	54.6	220
Example 8	2440	53.8	215
				Comparative example 1	2380	49.9	200
Comparative example 2	2390	49.6	200
				Comparative example 3	2390	50.1	200
Comparative example 4	2390	50.4	200
				Comparative example 5	2380	49.8	200
Comparative example 6	2380	49.7	200
				Comparative example 7	2390	50.0	200
Comparative example 8	2410	51.2	205
				Comparative example 9	2410	51.4	205
Comparative example 10	2390	51.6	205

As can be seen from table 5, the strength of the high-durability concrete of the present application can be improved when the hydroxypropyl cellulose, the triethyl citrate and the polyvinyl butyral are compounded, and none of the three components is acceptable; and the strength of the high-durability concrete can be further optimized when the cocoanut oil diethanol amide and the cocoanut oil aminopropyl dimethylamine ethyl lactone are compounded.

The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.

Claims (9)

1. A high-durability concrete is characterized in that: the raw materials comprise, by weight, 154 parts of 152-154 parts of water, 302 parts of 300-302 parts of cement, 76-78 parts of fly ash, 76-78 parts of slag powder, 55-57 parts of expanding agent, 436 parts of 434-436 parts of machine-made sand medium sand, 291 parts of machine-made sand fine sand 289-963 parts of stone and 14-17 parts of composite anti-cracking anti-seepage additive; the composite anti-cracking and anti-seepage additive comprises an anti-cracking and anti-seepage reinforcing agent, hydroxypropyl cellulose, triethyl citrate and polyvinyl butyral, wherein the weight ratio of the anti-cracking and anti-seepage reinforcing agent to the composite anti-cracking and anti-seepage additive is 8 (0.4-0.6) to 0.4-0.6 (0.4-0.6).

2. The high durability concrete of claim 1, wherein: the composite anti-cracking and anti-seepage additive also comprises cocoanut oil acid diethanolamide and cocoanut oil amide propyl dimethylamine ethyl lactone, wherein the weight ratio of the cocoanut oil acid diethanolamide to the anti-cracking and anti-seepage reinforcing agent is (0.2-0.4):8, and the weight ratio of the cocoanut oil amide propyl dimethylamine ethyl lactone to the anti-cracking and anti-seepage reinforcing agent is (0.2-0.4): 8.

3. The high durability concrete of claim 1, wherein: the anti-cracking and anti-seepage reinforcing agent is an HZ-2 type anti-cracking and anti-seepage reinforcing agent.

4. The high durability concrete of claim 1, wherein: the swelling agent is UEA-I type swelling agent.

5. The high durability concrete of claim 1, wherein: the cement is P. 042.5 Portland cement.

6. The high durability concrete of claim 1, wherein: the slag powder is S95-grade slag powder.

7. The high durability concrete of claim 1, wherein: the stones are 5-25mm continuous graded crushed stones.

8. The high durability concrete of claim 1, wherein: the fly ash is II type fly ash.

9. The method for producing a highly durable concrete according to any one of claims 1 to 8, wherein: the method comprises the following steps:

(1) adding the composite anti-cracking anti-seepage additive into water, and uniformly mixing to obtain an aqueous solution of the additive;

(2) mixing the stones, the machine-made sand medium sand and the machine-made sand fine sand, adding the mixture into a stirrer, and stirring for 15-20 seconds to uniformly mix the aggregates;

(3) adding 70% of the water solution of the additive into the stirrer, and stirring for 10-15 seconds to wet the mixed aggregate;

(4) adding cement, slag powder, fly ash and an expanding agent into a stirrer and stirring for 30-40 seconds;

(5) and adding the water solution of the additive with the residual 30 percent of the dosage into a stirrer, and stirring for 1-2 minutes to obtain the high-durability concrete.